| 摘要 |
PURPOSE:To stabilize blowing, to improve the quality of product steel and the yield of raw material and to reduce the cost for disintegrating a slag forming agent in an O2 top blown steel making method wherein gases are blown under the bath surface by charging a limited ratio of slag forming agents in the form of lump and adding the remaining part of the slag forming agent in the form of powder together with top blown O2. CONSTITUTION:<=70% of the entire amt. of >=1 kind slag forming agents such as quicklime, limestone, dolomite or the like to be added are charged in the form of lump from a chute S for charging raw material on a recovery hood for waste gas to the molten iron in a converter CV inserted therein with a lance L. If necessary, >=1 kind Mn ore and iron ore can be charged in this stage. The remaining part of the slag forming agents are carried by a gaseous carrier and are injected in the form of powder from the nozzle 15 in the central part of a nozzle head A of the lance and are guided without scattering into the bath by the gaseous O2 injected from 3 pieces of peripheral nozzles 16. The powder slag forming agents are added under such condition that the basicity of slag attains >=2 from the start of blowing to the end of desiliconization and during the time until the blowing end from at least 2min before the end of the blowing. |
